1. Field of the Invention
This invention relates in general to vehicular axle assemblies and in particular to a method for joining together vehicle components, especially those manufactured from dissimilar materials, to form such a vehicle axle assembly.
2. Background of the Invention
Axle assemblies are well known structures that are in common use in most vehicles. Such axle assemblies include a number of components, which are adapted to transmit rotational power from an engine of the vehicle to the wheels thereof. Typically, an axle assembly includes a differential assembly that is rotatably supported within a non-rotating carrier. The differential is connected between an input drive shaft extending from the vehicle engine and a pair of output axle shafts extending to the vehicle wheels. The axle shafts are contained in respective non-rotating beam portions, which are secured to the carrier. Thus, rotation of the differential by the drive shaft causes corresponding rotation of the axle shafts. The carrier and the beam portions form an axle housing for these drive train components of the axle assembly, inasmuch as the differential and the axle shafts are supported for rotation therein.
Axle housings are generally classified into two basic types. The first axle housing type is a unitized carrier construction, commonly referred to as a Salisbury or Spicer type axle assembly. In this structure, the carrier (which houses the differential assembly) is directly connected to the two beam portions (which house the rotatable axle shafts). An opening is provided at the rear of the carrier to permit assembly of the differential therein. A cover closes this opening during use. Unitized carrier axle housing constructions of this type are economical to manufacture and are readily adaptable for a variety of vehicles.
The second axle housing type is a separable carrier construction. In this structure, the axle beam portions are connected together by a central portion of the axle housing that is formed separate and apart from the differential carrier. This central portion is generally hollow and cylindrical in shape, having a large generally circular opening formed therethrough. During assembly, the differential is first assembled within the carrier, then the carrier is secured to the central member. The overall shape of this type of axle housing (i.e., the generally round shape of the central portion and the elongated beam portions extending therefrom) generally resembles the shape of a banjo musical instrument. Hence, this type of axle housing is commonly referred to as a banjo type axle housing. Banjo type axle housings are advantageous because the carrier and differential can be removed from the axle assembly for service without disturbing the other components thereof.
In the past, several methods have been employed to form axle housings, and many of these methods employ welding to form the housing.
In the past, virtually all of these axle assemblies have been manufactured from a metallic material. Steel has traditionally been the preferred material for manufacturing all of such vehicle axle components because of its relatively high strength, relatively low cost, and ease of manufacture. As mentioned above, vehicle axle housing assemblies manufactured from metallic materials have been secured together by conventional welding techniques. More recently, however, in an effort to reduce the weight of the vehicle axle assembly, it has been found desirable to use alternative materials to form some or all of the vehicle axle components. Thus, in some instances, it may be desirable to form some or all of the vehicle axle components from materials which cannot be easily secured together, or in some cases cannot be secured together at all by conventional welding techniques. For example, conventional welding techniques cannot be used to secure a metallic vehicle axle component to another non-metallic vehicle axle component. Thus, it would be desirable to provide a method for joining vehicle components together to form a vehicle axle assembly, where the components are formed from alternative materials, and particularly those components manufactured from dissimilar materials, such as metallic and non-metallic materials.
The above object as well as other objects not specifically enumerated are achieved by a method of joining axle housing components made from dissimilar materials, where the method includes providing a central carrier component, and providing a pair of hollow arm portions preferably made from a material which is dissimilar to the material used to make the carrier component. Thereafter, the arm portions are secured to the central carrier component using magnetic pulse welding techniques.
For example, where two generally conductive metallic components of similar or dissimilar material constitute the axle housing, a portion of one of the axle housing components may be positioned within a portion of the other of the components in an overlapping manner, thereby forming an overlapping portion. An inductor is positioned around the outer metallic band. The inductor is energized to generate a magnetic field for collapsing the outer and overlapping portion at a velocity sufficiently developed by an electromagnetic pulse to weld the outer and inner metallic components to each other, thereby securing the axle housing components together.
In another embodiment of the invention, the method of joining two axle housing components made from dissimilar materials where the outer member is both dissimilar and less or non-conductive, the process includes the steps of providing a first axle housing component of a metallic material, providing a second axle housing component made from a composite or non-conductive dissimilar material, the second axle housing component having a protrusion or locking feature, and positioning a portion of the first axle component within a portion of the second axle component in an overlapping manner, thereby forming an overlapping portion, where the protrusion is within the overlapping portion. A conductive metallic band is disposed around the overlapping portion, and an inductor is disposed around the metallic band. The inductor is energized to generate a magnetic field for collapsing the band about the overlapping portion at a velocity sufficiently developed by an electromagnetic pulse to weld the outer band and inner metallic component to each other, thereby securing the first and second axle housing components together, wherein the metallic band is also crimped over the protrusion securing the composite or non-conductive component to the inner metallic housing.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.